The flagella of the choanocyte cells that line the central cavity create a water current that moves through the sponge, and any food particles present in the water gets trapped in the collar, a structure at the base of the choanocyte cell made up of microvilli.

Despite their lack of complexity, sponges are clearly successful organisms, having persisted on Earth for more than half a billion years. Sponges are monoecious (or hermaphroditic), meaning one individual can produce both eggs and sperm. Explanation: digestive process in cnidarians differ from sponges. Nematocysts contain coiled threads that may bear barbs.

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C. polymorphs 1. i) sponges have intracellular digestive system. If the installation of the insulation will cost $250 for materials and labor, determine how long it will take for the insulation to pay for itself from the energy it saves. The large central opening in the poriferan body is called the _____. Have questions or comments? Cnidarians have separate sexes. 2. • Cnidarians belong to Phylum Cnidaria. Sponges are similar to what might have been the ancestor of animals: colonial, flagellated protists. Food is taken into the gastrovascular cavity , enzymes are secreted into the cavity, and the cells lining the cavity absorb the nutrient products of the extracellular digestive process. Cnidarians perform extracellular digestion, with digestion completed by intracellular digestive processes. All sponges are aquatic and the majority of species are marine. The kingdom of animals is informally divided into invertebrate animals, those without a backbone, and vertebrate animals, those with a backbone. This process is called intracellular digestion.

Cnidarians possess a well-formed digestive system and carry out extracellular digestion. The class Anthozoa includes all cnidarians that exhibit a sessile polyp body plan only; in other words, there is no medusa stage within their life cycle. All cnidarians have two tissue layers. A type of asexual reproduction found only in freshwater sponges occurs through the formation of gemmules, clusters of cells surrounded by a tough outer layer.

To what kingdom do cnidarians belong? A mouth opening is surrounded by tentacles bearing cnidocytes (Figure 15.2.5). Early larval development occurs within the sponge, and free-swimming larvae are then released through the osculum.